Apparatus, method for distance measurement, and non-transitory computer-readable storage medium

Abstract

An apparatus for distance measurement includes: a memory; and a processor coupled to the memory and configured to execute a detection process that includes detecting a measurement target in a measurement range through two-dimensional scanning of a scan angle range with laser light, and execute a changing process that includes changing a width of the scan angle range with the laser light so that sampling density has a certain value or higher based on a distance and a bearing angle from the apparatus to the measurement target.

What is claimed is: 
     
       1. An apparatus for distance measurement, the apparatus comprising:
 a memory; and 
 a processor coupled to the memory and configured to
 execute a detection process that includes detecting a measurement target from among a distance image obtained by two-dimensional scanning of a scan angle range with laser light, the detected measurement target being a moving object, 
 execute a calculating process that includes
 obtaining a distance between the apparatus and a position of the detected measurement target, 
 obtaining a bearing angle from the apparatus to the detected measurement target, and 
 calculating a scan angle range and a shift value of the scan angle range in accordance with the obtained distance and the obtained bearing angle, the calculating of the scan angle range being configured to calculate the scan angle range such that sampling density within the scan angle range is equal or higher than a certain value, the calculating of the shift value being configured to calculate the shift value such that the detected measurement object is included in a center of the calculated scan angle range, and 
 
 execute a changing process that includes updating an operation parameter in the two-dimensional scanning by using the calculated scan angle range and the calculated shift value, thereby the distance image obtained by the two-dimensional scanning based on the updated operation parameter includes the measurement target even if a position of the measurement target has been changed. 
 
 
     
     
       2. The apparatus according to  claim 1 ,
 wherein the changing process includes shifting a center of the scan angle range with the laser light based on the bearing angle or an estimated position of the measurement target. 
 
     
     
       3. The apparatus according to  claim 1 ,
 wherein the changing process includes, when the sampling density is lower than the sampling density having a certain value or higher in a maximum scan angle range with the laser light, setting the scan angle range to the maximum scan angle range. 
 
     
     
       4. The apparatus according to  claim 3 ,
 wherein the changing process includes, when the scan angle range is the maximum scan angle range and the sampling density exceeds a threshold value, controlling light emission timing of the laser light so that the sampling density is lower than or equal to the threshold value. 
 
     
     
       5. The apparatus according to  claim 3 ,
 wherein the changing process includes, when the scan angle range is the maximum scan angle range and the sampling density exceeds a threshold value, decimating a result of measurement so that the sampling density is lower than or equal to the threshold value. 
 
     
     
       6. The apparatus according to  claim 1 ,
 wherein the changing process includes calculating the bearing angle based on distance data measured through the scanning with the laser light and mirror angle data for a scanning mirror that deflects the laser light. 
 
     
     
       7. The apparatus according to  claim 1 ,
 wherein the processor is configured to execute an imaging process, the imaging process including acquiring an image captured by a camera having an angle of view wider than the scan angle range, and 
 wherein the changing process includes calculating the bearing angle based on distance data measured through the scanning with the laser light and the image captured by the camera having the angle of view wider than the scan angle range. 
 
     
     
       8. A method for distance measurement, the method comprising:
 executing, by processor circuitry, a detection process that includes detecting a measurement target from among a distance image obtained by two-dimensional scanning of a scan angle range with laser light, the detected measurement target being a moving object; 
 executing, by the processor circuitry, a calculating process that includes
 obtaining a distance between the apparatus and a position of the detected measurement target, 
 obtaining a bearing angle from the apparatus to the detected measurement target, and 
 calculating a scan angle range and a shift value of the scan angle range in accordance with the obtained distance and the obtained bearing angle, the calculating of the scan angle range being configured to calculate the scan angle range such that sampling density within the scan angle range is equal or higher than a certain value, the calculating of the shift value being configured to calculate the shift value such that the detected measurement object is included in a center of the calculated scan angle range; and 
 
 executing, by the processor circuitry, a changing process that includes updating an operation parameter in the two-dimensional scanning by using the calculated scan angle range and the calculated shift value, thereby the distance image obtained by the two-dimensional scanning based on the updated operation parameter includes the measurement target even if a position of the measurement target has been changed. 
 
     
     
       9. The method according to  claim 8 ,
 wherein the changing process includes shifting a center of the scan angle range with the laser light based on the bearing angle or an estimated position of the measurement target. 
 
     
     
       10. The method according to  claim 9 ,
 wherein the changing process includes, when the sampling density is lower than the sampling density having a certain value or higher in a maximum scan angle range with the laser light, setting the scan angle range to the maximum scan angle range. 
 
     
     
       11. The method according to  claim 10 ,
 wherein the changing process includes, when the scan angle range is the maximum scan angle range and the sampling density exceeds a threshold value, controlling light emission timing of the laser light so that the sampling density is lower than or equal to the threshold value. 
 
     
     
       12. The method according to  claim 10 ,
 wherein the changing process includes, when the scan angle range is the maximum scan angle range and the sampling density exceeds a threshold value, decimating a result of measurement so that the sampling density is lower than or equal to the threshold value. 
 
     
     
       13. The method according to  claim 8 ,
 wherein the changing process includes calculating the bearing angle based on distance data measured through the scanning with the laser light and mirror angle data for a scanning mirror that deflects the laser light. 
 
     
     
       14. The method according to  claim 8 ,
 wherein the processor is configured to execute an imaging process, the imaging process including acquiring an image captured by a camera having an angle of view wider than the scan angle range, and 
 wherein the changing process includes calculating the bearing angle based on distance data measured through the scanning with the laser light and the image captured by the camera having the angle of view wider than the scan angle range. 
 
     
     
       15. A non-transitory computer-readable storage medium storing a program that causes processor circuitry to execute a process for distance measurement, the process comprising:
 executing a detection process that includes detecting a measurement target from among a distance image obtained by through two-dimensional scanning of a scan angle range with laser light, the detected measurement target being a moving object; 
 executing a calculating process that includes
 obtaining a distance between the apparatus and a position of the detected measurement target, 
 obtaining a bearing angle from the apparatus to the detected measurement target, and 
 calculating a scan angle range and a shift value of the scan angle range in accordance with the obtained distance and the obtained bearing angle, the calculating of the scan angle range being configured to calculate the scan angle range such that sampling density within the scan angle range is equal or higher than a certain value, the calculating of the shift value being configured to calculate the shift value such that the detected measurement object is included in a center of the calculated scan angle range; and 
 
 executing a changing process that includes updating an operation parameter in the two-dimensional scanning by using the calculated scan angle range and the calculated shift value, thereby the distance image obtained by the two-dimensional scanning based on the updated operation parameter includes the measurement target even if a position of the measurement target has been changed. 
 
     
     
       16. The non-transitory computer-readable storage medium according to  claim 15 ,
 wherein the changing process includes shifting a center of the scan angle range with the laser light based on the bearing angle or an estimated position of the measurement target. 
 
     
     
       17. The non-transitory computer-readable storage medium according to  claim 16 ,
 wherein the changing process includes, when the sampling density is lower than the sampling density having a certain value or higher in a maximum scan angle range with the laser light, setting the scan angle range to the maximum scan angle range. 
 
     
     
       18. The non-transitory computer-readable storage medium according to  claim 17 ,
 wherein the changing process includes, when the scan angle range is the maximum scan angle range and the sampling density exceeds a threshold value, controlling light emission timing of the laser light so that the sampling density is lower than or equal to the threshold value. 
 
     
     
       19. The non-transitory computer-readable storage medium according to  claim 17 ,
 wherein the changing process includes, when the scan angle range is the maximum scan angle range and the sampling density exceeds a threshold value, decimating a result of measurement so that the sampling density is lower than or equal to the threshold value. 
 
     
     
       20. The non-transitory computer-readable storage medium according to  claim 15 ,
 wherein the changing process includes calculating the bearing angle based on distance data measured through the scanning with the laser light and mirror angle data for a scanning mirror that deflects the laser light.